1. Field of the Invention
The invention relates to a device for coating the internal surfaces of elongate hollow spaces, such as ducts or channels, which device comprises a shield substantially corresponding to the cross section of the hollow space and capable of being displaced in the longitudinal direction of the hollow space by means of a bogie connected therewith, which shield is connected with supply ducts for a curable mass being in the plastic state, which supply ducts are provided with outlet openings substantially uniformly distributed about the periphery of the cross section of the hollow space, wherein a blower is provided with a seat for a flexible tube capable of being pressed at the hollow space to be coated and substantially air-tight relative to the inner side and comprises a supporting means capable of being stationarily anchored within the hollow space. The invention, furthermore, relates to a process for applying a coating of a fiber-reinforced curable mass including a binder onto a substrate, in particular, the internal wall of a channel or the like, using such a device.
2. Prior Art
With known processes of this type, such fibers in the preparation of a curable mass are admixed, optionally in the form of bundles of fibers held together by aid of a binder dissolving in the mass. In doing so, the problem arises that a sufficiently uniform distribution of the fibers, whose specific weight usually is considerably lower than that of the mass, in the same frequently is only very hard to obtain involving considerable expenditures. Moreover, the filling ratio of the mass with fibers obtained in this manner is rather moderate.
A method of this type has become known, for instance, from WO-A 93/13350, wherein a layer of mutually engaging fibers is applied onto a substrate and this layer is soaked with a mass being in the plastically deformable state, whereupon the mass is allowed to cure.
Furthermore, devices for coating the internal walls of hollow bodies, e.g., channels are known. Examples for such devices are described, for instance, in DE-A 39 31 775 or DE-A 41 26 310.
In the known devices, there is provided a tubular encasing which externally comprises a peripheral seal projecting towards the internal wall of a channel to be coated. Viewed in the advance direction of the device, the outflow openings of the supply ducts for the curable mass are provided behind the seal. That region is followed by a region in which an elastically widenable flexible tube attached to the outer side of the encasing is inflatable by compressed air in order to distribute, and coarsely smooth, the emerging curable mass. Behind that region, a shield is arranged, which is comprised of spreadable segments and serves to smoooth the coating applied. In the device moving in the advance direction, the shield constitutes the end of the same.
Such a device involves the drawback of being very heavy and bulky. Due to a considerable friction prevailing between the seal and the inflatable flexible tube and, last but not least, between the shield and the internal wall of the hollow space to be coated, the device, moreover, requires a highly efficient actuating means in order to be able to move the device at all, which brings about problems also in respect of the transmission of the driving force to the internal wall of the hollow space. In addition, coatings strongly enriched with fibers cannot be readily applied by means of said known devices.